JP2021179525A - Display device - Google Patents

Abstract

To provide a display device which suppresses the reduction in the contract and the reduction in the color purity of the display even the higher definition is realized, and suppresses the reduction in the visibility without using a circularly polarized light plate.SOLUTION: A display device 51 comprises: a first substrate 100 which has a first surface 100a; a second substrate 200 which has a second surface and is arranged such that the second surface faces the first surface; a black matrix 6 which is provided in the matrix shape on the first surface and has a plurality of openings; a transmittance adjustment layer 5 which is provided between the first surface and the black matrix and contains carbon; a plurality of light-emitting units 4 which are arranged in the matrix shape on the second surface and include light-emitting elements; a light reflection partition wall 1 which is provided in the matrix shape on the second surface and surrounds the plurality of light-emitting units in the plan view; and a light absorptive partition wall 2 which contains carbon, is provided in the matrix shape and is provided between the first surface and the light reflection partition wall.SELECTED DRAWING: Figure 1

Description

The present invention relates to a display device, more specifically a display device including a light emitting element.

An organic electroluminescence display device (hereinafter referred to as organic EL) is known as a display device, but the light emission efficiency of the organic EL layer is low, the light emission changes with time, the life is short, and the current is current. There is a problem that seizure is likely to occur when the amount is increased.
Recently, as a display device that contributes to the thinning of mobile devices, a display device (LED display) using an LED composed of an inorganic material is expected. The LED has higher luminous efficiency than the organic EL, and the emission luminance can be easily adjusted by the amount of current (a brighter display can be made), so that the degree of attention is improved.

In recent years, a technique of using a direct-type backlight called a mini LED, which has a configuration in which a plurality of LED chips having a size of about 5 μm to 200 μm are arranged in a matrix, is attracting attention as a liquid crystal display device. There are two types of mini LEDs, one is a method of using three types of LED chips of red light emission, green light emission, and blue light emission to make full color, and the other is a method of using a blue light emitting LED chip as a light source to convert the wavelength of blue light to make full color.

Attention is being paid to a technique of partially adjusting the emission brightness of three types of LED chips according to the position of a display portion on a display screen, or by using local dimming in which light emission is partially stopped.
In a liquid crystal display device using local dimming, the light emission on the display screen can be partially turned off, so that the contrast of the display can be greatly improved. In the conventional liquid crystal display device, since the backlight is always lit, a slight light leakage occurs when the liquid crystal is displayed in black, and it is difficult to obtain a contrast comparable to that of an organic EL. A liquid crystal display device using local dimming is equivalent to an organic EL in terms of contrast, and is superior to an organic EL in terms of power consumption and life.

In addition, a structure called a micro LED in which LED chips having a size of about 2 μm to 50 μm are arranged in a matrix is also known. Since the display device using the micro LED displays by individually driving each of the plurality of LED chips, the display can be performed without using the liquid crystal display.

Patent Document 1 describes a liquid crystal display device including a liquid crystal panel and a backlight device. The light emitting element of the backlight device is a blue LED, and the light emitted from the blue LED passes through the diffuser plate and the phosphor sheet 65 to become surface-uniform white light.

International Publication No. 2017/191714

In both the micro LED and the mini LED, the light emitted from the LED chip may enter the adjacent pixels as stray light, resulting in a decrease in display contrast and a decrease in color purity. This possibility increases as the definition of display devices increases.

In a light emitting element such as an LED or an organic EL, it is common to provide a light-reflecting electrode (hereinafter, referred to as a “reflection electrode”) at a position facing the viewing side. In such a configuration, there is also a problem that the external light (sunlight or light from a lamp in the room) incident from the visual recognition side is reflected and enters the observer's eyes, which greatly reduces the visibility. To solve this problem, a circularly polarizing plate is usually attached to the surface of a display device to cut off external light reflection from a reflecting electrode. However, since the circularly polarizing plate is expensive and requires an extra step of attaching the circularly polarizing plate, it is desired to omit the circularly polarizing plate.

Patent Document 1 does not consider any of the above-mentioned problems, and does not disclose a technical idea for solving them.

In view of the above circumstances, it is an object of the present invention to provide a display device in which a decrease in display contrast and a decrease in color purity are unlikely to occur even when high definition is advanced, and a decrease in visibility is suppressed without using a circularly polarizing plate. ..

The present invention has a first substrate having a first surface, a second substrate having a second surface and arranged with the second surface facing the first surface, and a matrix on the first surface. A black matrix provided with a plurality of openings, a transmittance adjusting layer provided between the first surface and the black matrix, and a light emitting element arranged in a matrix on the second surface. A plurality of light emitting units including the above, a light-reflecting partition wall provided in a matrix on the second surface and surrounding the plurality of light emitting units in a plan view, and a matrix containing carbon, the first surface and the above. It is a display device including a light-absorbing partition wall arranged between the light-reflecting partition wall and the light-absorbing partition wall.

According to the present invention, it is possible to provide a display device in which a decrease in display contrast and a decrease in color purity are unlikely to occur even when high definition is advanced, and a decrease in visibility is suppressed without using a circularly polarizing plate.

It is a partial cross-sectional view of the display device which concerns on 1st Embodiment of this invention. It is an enlarged view of the part A in FIG. It is a schematic cross-sectional view of the wiring which concerns on the display device. It is a partial cross-sectional view of the display device which concerns on 2nd Embodiment of this invention. It is a partial cross-sectional view which shows the modification of the display device.

Hereinafter, the first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
In the following description, the same or substantially the same functions and components are designated by the same reference numerals, and the description thereof will be omitted or simplified, or the description will be given only when necessary. Further, if necessary, elements that are difficult to show, such as a thin film transistor, a structure of a plurality of layers constituting a conductive layer, a wiring connection to a circuit portion, a switching element (transistor), etc. are shown or partly shown. Illustration may be omitted.
In each embodiment, characteristic parts will be described, and for example, parts that are not different from the components used in a normal display device will be omitted as appropriate.

Ordinal numbers such as "first" and "second" in each composition are attached to avoid confusion of the components, and the order and quantity are not specified.
The "matrix arrangement of light emitting elements" refers to an arrangement in which light emitting units including one or more light emitting elements are arranged in a matrix at a constant pitch in a plan view. In the following description, a matrix of light emitting elements may be referred to as an "optical module".
The light emitting unit is surrounded by a black matrix having a grid pattern in a plan view as a display device. The light emitting unit surrounded by the black matrix in a plan view includes one or more light emitting elements which are light emitting diodes. In a display device using the local dimming technique described later, the drive on / off and the brightness of light emission can be adjusted by, for example, a unit of a light emitting unit including one or more light emitting elements, or a plurality of light emitting units. In the local dimming technique, the number of pixels can be increased among the number of light emitting elements and the number of pixels included in the light emitting unit in a plan view. In other words, it can be said that the efficient drive of the display device by the number of light emitting elements smaller than the number of pixels is the merit of local dimming.

The term "planar view" as used herein means that the observer views the display device according to the present invention in the normal direction from the first substrate side.

FIG. 1 is a partial cross-sectional view of the display device 51 according to the present embodiment. The display device 51 includes a black matrix substrate (hereinafter, referred to as “BM substrate”) 10 having a first substrate 100 and an optical module substrate 20 having a second substrate 200.

As shown in FIG. 1, the BM substrate 10 is formed on a transparent first substrate 100, a transmittance adjusting layer 5 formed on the first surface 100a of the first substrate 100, and a transmittance adjusting layer 5. The black matrix 6 is provided with a first transparent resin layer 21 formed so as to cover the black matrix 6, and a light-absorbing partition wall 2 formed on the first transparent resin layer 21.

The first substrate 100 is transparent. As the material of the first substrate 100, glass is typical, and quartz, sapphire, plastic and the like can be exemplified. As the plastic, polyimide can be exemplified.

The transmittance adjusting layer 5 is a resin layer in which carbon is dispersed. The thickness of the transmittance adjusting layer 5 is preferably in the range of, for example, 0.4 μm to 1 μm, but may be 1 μm or more. The transmittance adjusting layer 5 may further contain an organic pigment such as blue or yellow in addition to carbon.

The transmittance adjusting layer 5 can be formed by using a resin dispersion containing carbon. The visible light transmittance of the transmittance adjusting layer 5 can be adjusted by the carbon content, and is preferably in the range of 70% to 99.5%. When the visible light transmittance is 99.6% or more, ripple is likely to occur due to the interference of external light reflection, and the display quality of the display device in "black display" is likely to be impaired. If the transmittance of the transmittance adjusting layer 5 is less than 70%, the brightness of the display is lowered, which is not preferable. Further, when the transmittance is less than 70%, the reflectance at the interface with the first substrate 100 tends to be high. The display quality can be improved by setting the reflectance at the interface between the transmittance adjusting layer 5 and the first substrate 100 when the black matrix 6 is used as a base in a low range of 0.3% to 1%.
As the resin constituting the transmittance adjusting layer 5, substantially the same material as the material of the light-absorbing partition wall or the black matrix described later can be applied.

The transmittance adjusting layer 5 may contain transparent fine particles made of an inorganic oxide or a resin. Examples of the inorganic oxide include SiO ₂ (silicon dioxide) and the like. Since _{the refractive index of SiO 2} is smaller than that of carbon, the refractive index of the transmittance adjusting layer 5 is lowered by adding _{SiO 2.} The transmittance adjusting layer 5 having a low refractive index has an effect of suppressing light reflection at the interface with the black matrix 6 and improving visibility. The addition of transparent fine particles also has the advantage of improving the dispersibility of carbon.

The transmittance adjusting layer 5 containing carbon has a flat reflected light and is hardly colored. "The reflected light is flat" means that in the visible range of 400 nm to 700 nm, in a small range such as 100 nm, the fluctuation range of the transmittance is less than 2%, and the transmittance curve becomes almost a straight line. Means that.

The black matrix 6 forms a grid pattern in the plan view of the BM substrate 10. The basic structure of the black matrix 6 is known, and can be formed, for example, by patterning a black layer formed of a black photosensitive resist in a desired lattice pattern using a photolithography technique (exposure / development / dura mater).
Normally, the black matrix used in a display device is required to have a high light-shielding property as well as black color, and therefore, it is preferable that the optical density in the visible region is 3 or more.
The first transparent resin layer 21 covers the entire transmittance adjusting layer 5 including the black matrix 6. As shown in FIG. 1, the upper surface of the first transparent resin layer 21 preferably absorbs the thickness of the black matrix 6 and is flattened.

The light-absorbing partition wall 2 is formed in a matrix on the first transparent resin layer 21, and is in a grid pattern in a plan view.
The light-absorbing partition wall 2 contains carbon. As the carbon, carbon having a low wavelength selectivity of visible light is preferable. "Low wavelength selectivity of visible light" means that light in the wavelength range of 400 nm to 700 nm has almost no coloration of absorbed or reflected light and visually exhibits a black or gray color. ..
When the light-absorbing partition wall 2 is formed of a carbon dispersion of a resin, a photolithography method can be applied. When the light-absorbing partition wall 2 is formed by a photolithography method, an alkali-soluble photosensitive resin can be used.
As the photosensitive resin, a (meth) acrylic compound or Keihi having a reactive substituent such as an isocyanate group, an aldehyde group or an epoxy group on a linear polymer having a reactive substituent such as a hydroxyl group, a carboxyl group or an amino group or Keihi. An example thereof is a resin in which a photobridgeable group such as a (meth) acryloyl group or a styryl group is introduced into the linear polymer by reacting with an acid.
Examples of the monomer and oligomer that are precursors of the transparent resin include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, polyethylene glycol di (meth) acrylate, and pentaerythritol tri (meth). ) Acrylate, Trimethylol Propanetri (meth) Acrylate, Dipentaerythritol Hexa (meth) Acrylate, Tricyclodecanyl (meth) Acrylate, Melamine (Meta) Acrylate, Epoxy (Meta) Acrylate, etc. Examples thereof include esters, (meth) acrylic acid, styrene, vinyl acetate, (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, acrylonitrile and the like. These can be used alone or in combination of two or more. When the photosensitive resin is cured by using ultraviolet rays having a wavelength of about 365 nm, a photopolymerization initiator or the like may be further added.
In the carbon dispersion of the resin, the transmittance of the exposure wavelength (for example, 365 nm) is preferably in the range of 0.1% or more and 10% or less. If the transmittance of the exposure wavelength is less than 0.1%, the exposure is not sufficient, and the light-absorbing partition wall 2 is likely to be peeled off during alkaline development. When the transmittance of the exposure wavelength exceeds 10%, visible light is likely to be transmitted to the adjacent pixels, so that the color purity related to the display is lowered.
In the plan view of the first substrate 100, the grid of the light absorbing partition wall 2 overlaps with the grid of the black matrix 6. As a result, in the plan view of the first substrate 100, the center of the first opening 35 surrounded by the grid of the black matrix 6 and the second opening 36 surrounded by the grid of the light absorbing partition wall 2 are aligned or abbreviated. They match and overlap.

The optical module substrate 20 has a second substrate 200, a plurality of light emitting units 4 arranged on one surface (second surface) 200a of the second substrate 200, and a light reflecting partition wall 1.
The light emitting unit 4 has at least one LED 3 as a light emitting element. As the LED 3, an element that emits light having an arbitrary wavelength can be selected. For example, as an element that emits blue or green light, a light emitting element using a nitride semiconductor such as InAlGaN can be used. Further, as the LED 3, a light emitting device containing a semiconductor such as GaAlAs, AlInGaP, GaAsP, GaP, GaN, or InGaN can be used. Further, a semiconductor light emitting device made of a material other than these can also be used. Various emission wavelengths can be selected depending on the material of the semiconductor layer in the semiconductor laminated structure and the mixed crystal ratio thereof. The composition, emission color, size, number, etc. of the light emitting element to be used may be appropriately selected according to the purpose.
Although FIG. 1 shows a vertical LED as the LED 3, a horizontal LED can also be used. In the case of a horizontal LED, the mounting method may differ between the face-up type (both the p-side electrode and the n-side electrode are located on the upper side) and the face-down type (both the p-side electrode and the n-side electrode are located on the lower side). be. In the case of face-up, a wire bonding technique using a gold wire can be applied. In the case of face-down, mounting with a low melting point metal such as an anisotropic conductive film or an In alloy can be applied.
The LED is connected to a transistor array 210 including a thin film transistor (TFT) formed on the second substrate 200, and can be driven by the transistor array 210.

FIG. 2 is an enlarged view of part A in FIG. The upper electrode 16 of the vertical LED 3 is electrically connected to the transparent conductive film 29 via a contact hole formed in the transparent resin layer No. 1. The lower electrode 17 is connected to the reflective electrode 31 via the bonding layer 34. The reflective electrode 31 is connected to the drain electrode 89 of the transistor array 210 via the contact hole 42.

As the bonding layer 34, for example, a conductive material capable of connecting the lower electrode 17 and the reflecting electrode 31 by fusion within the temperature range of 150 ° C. to 340 ° C. can be applied. As this conductive material, a material in which a conductive aggregate such as silver, carbon, or graphite is dispersed in a heat-flowing resin can be exemplified. In addition, the anisotropic conductive film can be used as the bonding layer 34.
As the bonding layer 34, In (indium), InBi alloy, InSb alloy, InSn alloy, InAg alloy, InGa alloy, SnBi alloy, SnSb alloy, etc., or a low melting point metal which is a ternary system or a quaternary system of these metals is also used. can. Since these low melting point metals have good wettability to conductive metal oxides including In oxide, after roughly aligning the lower electrode 17 and the reflecting electrode 31, the lower electrode 17 and the reflecting electrode 31 are self-aligned. It can be fused consistently. As the energy required for fusion, various energies such as heat, pressurization, electromagnetic waves, laser light, and the combined use of these and ultrasonic waves are used.
The vertical LED has an advantage that it is easy to repair when a poor connection occurs. Horizontal LEDs in which electrodes are lined up in the same direction have the disadvantages that it is difficult to perform a junction inspection of individual elements and that the electrodes are easily short-circuited during repair (replacement of defective diodes, etc.). From this point of view, vertical LEDs are preferably used. The bonding layer 34 can be formed into a desired pattern by a well-known photolithography method or lift-off means after film formation such as vacuum film formation.

The reflective electrode 31 contains silver (Ag) having a high reflectance of visible light, a silver alloy, and aluminum (Al). Silver has excellent visible light reflectance, but silver has low adhesion to many substrate materials and glass substrates. In addition, the surface of silver tends to form oxides and sulfides, and is not easy to mount electrically. Aluminum has a drawback that it is difficult to obtain ohmic contact with an indium-containing oxide such as ITO.
In consideration of the above, the reflective electrode 31 in the present embodiment has a three-layer structure in which the metal layer 45 is sandwiched between the conductive oxide layers 46, as shown in FIG. As a result, the above-mentioned drawbacks of silver and aluminum are compensated for by the conductive oxide layer 46.

Examples of the material of the metal layer 45 include silver, a silver alloy, aluminum, copper, and a copper alloy. Copper and copper alloys are not the best as a reflective electrode 31 because the reflected light is reddish, but they can be applied to a wiring portion connected to a TFT or a portion functioning as a gate wiring without any problem. From such a viewpoint, the metal layer 45 may contain two or more kinds of metals.
The metal layer 45 can be formed by vacuum film formation such as sputtering. The thickness of the metal layer 45 can be 100 nm or more and 500 nm or less.

As the conductive oxide forming the conductive oxide layer 46, a composite oxide of indium oxide or zinc oxide can be exemplified. In ITO (a mixed oxide containing indium oxide and tin oxide), which is typical as a conductive oxide, the metal contained in the conductive oxide is noble than the metal of the metal layer 45. Therefore, when the reflective electrode 31 is patterned, the metal layer 45 is selectively etched, and the line width tends to be different between the conductive oxide layer 46 and the metal layer 45 in a plan view. The corrosion potential is adjusted by adding easily soluble oxides such as zinc oxide, gallium oxide, and antimony oxide to indium oxide, and the silver alloy layer (or copper alloy layer) and the mixed oxide layer having the same corrosion potential are formed. Then, this phenomenon can be suppressed.
The thickness of the conductive oxide layer 46 is not particularly limited, but may be, for example, 10 nm or more and 500 nm or less.

In the present embodiment, the channel layer 40 of the transistor array is formed of an oxide semiconductor.
As oxide semiconductors, In-Ga-Zn-O film, In-Sn-Zn-O film, In-Al-Zn-O film, Sn-Ga-Zn-O film, Al-Ga-Zn-O film, Sn-Al-Zn-O system, In-Zn-O film which is a binary metal oxide, Sn-Zn-O film, Al-Zn-O film, Zn-Mg-O film, Sn-Mg- A metal oxide film such as an O film, an In—Mg—O film, an In—Sb—O film, an In—O film, a Sn—O film, and a Zn—O film can be used. Here, for example, the In-Sn-Ga-Zn-O film means a composite oxide film having indium (In), tin (Sn), gallium (Ga), and zinc (Zn). In addition, in order to reduce oxygen deficiency in oxide semiconductors, as stabilizers for the oxidation state, zirconium oxide, hafnium oxide, scandium oxide, yttrium oxide, lanthanum oxide, cerium oxide, neodymium oxide, samarium oxide, erbium oxide, gallium oxide , Titanium oxide and magnesium oxide are preferably added to the oxide semiconductor. When a high electron concentration is required for the channel layer, it is possible by increasing the addition ratio of tin oxide.

A transistor provided with a channel layer 40 made of an oxide semiconductor can obtain a larger current than a transistor having amorphous silicon as a channel layer, and is suitable for display using an LED, an organic EL, or the like as a light emitting element.
A transistor having polysilicon as a channel layer has a laser annealing process in its manufacturing process. Since the laser annealing step is difficult to apply to a large substrate, it is difficult to apply a transistor array having polysilicon as a channel layer to a large display such as a large TV or signage.
The transistor array 210 of the present embodiment provided with the channel layer 40 has a small process load in manufacturing. As a result, the display device can be manufactured at low cost regardless of the display size.

In the present embodiment, each wiring of the transistor array 210 has a three-layer structure similar to that of the reflective electrode 31. Since it is not necessary to consider the reflected light in each wiring of the transistor array 210, copper, a copper alloy, or the like can be used as the metal layer 45 without any problem.
When silver wiring or copper wiring is applied to wiring such as a gate wire or a source wire of a TFT, the annealing (heat treatment) temperature for stabilizing the electrical characteristics of the channel layer may become a problem. When the annealing temperature is higher than 340 ° C., silver and copper are likely to diffuse into the surrounding insulating layer, and the characteristics of the TFT are likely to be deteriorated. From this point of view, the above-mentioned three-layer structure is effective, and it is important to select a layer made of an oxide semiconductor that can be crystallized at 340 ° C. or lower as the oxide semiconductor layer.
A mixed oxide using antimony oxide, bismuth oxide, and indium oxide as a base material can be annealed at a low temperature, and can be said to be a suitable example of the above oxide semiconductor.

The light reflective partition wall 1 is formed on the transistor array 210. The light-reflecting partition wall 1 has a structure in which the surface of the resin core 1a is covered with a metal thin film 1b. The light-reflecting partition wall 1 is formed in a matrix shape, and is in a grid shape in a plan view of the optical module substrate 20. In the plan view of the optical module substrate 20, at least one light emitting unit is arranged in the third opening surrounded by the light reflecting partition wall 1.

The core 1a can be formed by patterning an alkali-soluble photosensitive resin by a well-known photolithography technique or by patterning a layer of a thermosetting resin by a dry etching technique. The height (thickness) of the core 1a can be 1 μm or more and 50 μm or less.
As the photosensitive resin, a (meth) acrylic compound or Keihi having a reactive substituent such as an isocyanate group, an aldehyde group or an epoxy group on a linear polymer having a reactive substituent such as a hydroxyl group, a carboxyl group or an amino group or Keihi. An example thereof is a resin in which a photobridgeable group such as a (meth) acryloyl group or a styryl group is introduced into the linear polymer by reacting with an acid.
Examples of the monomer and oligomer that are precursors of the transparent resin include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, polyethylene glycol di (meth) acrylate, and pentaerythritol tri (meth). ) Acrylate, Trimethylol Propanetri (meth) Acrylate, Dipentaerythritol Hexa (meth) Acrylate, Tricyclodecanyl (meth) Acrylate, Melamine (Meta) Acrylate, Epoxy (Meta) Acrylate, etc. Examples thereof include esters, (meth) acrylic acid, styrene, vinyl acetate, (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, acrylonitrile and the like. These can be used alone or in combination of two or more. When the photosensitive resin is cured by using ultraviolet rays having a wavelength of about 365 nm, a photopolymerization initiator or the like may be further added.

The metal thin film 1b can be executed by a vacuum film forming method such as vacuum vapor deposition or sputtering, and various reflective metal materials such as aluminum, aluminum alloy, silver, and silver alloy can be used as the material. These metallic materials may contain dissimilar elements in an amount of 0.5 at% or more and 5 at% or less.

A transparent protective layer 15 is formed on the light-reflecting partition wall 1. The material of the transparent protective layer 15 is a transparent resin. The transparent protective layer 15 is patterned by etching, photolithography, or the like, and a part of the upper surface of the light-reflecting partition wall 1 and at least a part of the upper electrode 16 of the LED 3 are exposed without being covered by the transparent protective layer 15. ..
A transparent conductive film 29 is formed on the transparent protective layer 15, and in the contact holes 41 and the contact grooves 43 formed in the transparent protective layer 15, the transparent conductive film 29 electrically connects the metal thin film 1b and the upper electrode 16. It is connected to the. The plan view shape of the contact portion to which the transparent conductive film 29 is connected can be appropriately set to be circular, polygonal, or the like.

The metal thin film 1b is connected to a power supply (not shown) of the LED 3. As a result, the upper electrode 16 is fed via the metal thin film 1b and the transparent conductive film 29.
Each LED 3 has a switch (not shown) in the circuit, and is configured to be independently able to be driven on and off.

The display device 51 is configured by arranging the first surface 100a side of the BM substrate 10 and the second surface 200a of the optical module substrate 20 so as to face each other. In the plan view of the display device 51, the light-reflecting partition wall 1 is located within the range in which the light-absorbing partition wall 2 is provided. As a result, each LED 3 is located at the center of the first opening 35 of the black matrix 6, the second opening 36 of the light absorbing partition wall 2, and the lattice opening of the light reflecting partition wall 1 in the plan view of the display device 51. doing.

The display device 51 of the present embodiment has the simplest configuration among the display devices according to the present invention, and functions as a monochrome display device by functioning as one pixel for each opening corresponding to each LED 3.
Since the light emitted from the ON-driven LED 3 is diffused light, a part of the light is not incident on the second opening 36 of the overlapping BM substrate 10 in a plan view. Such light becomes stray light and deteriorates the display quality.
In the display device 51 of the present embodiment, the generation of stray light is suppressed and high display quality is maintained even if the definition is improved by the following actions.
A part of the diffused light is reflected by the light-reflecting partition wall 1 and is suitably guided to the corresponding second opening 36.
Most of the light that goes out of the optical module board 20 and does not enter the corresponding opening of the BM board 10 hits the light-absorbing partition wall 2 and is absorbed.
Light that passes through the second opening 36 of the light-absorbing partition wall 2 and does not go into the overlapped first opening 35 hits the light-absorbing partition wall 2 and the black matrix 6 and is absorbed.

Further, in the display device 51 of the present embodiment, the contrast decrease due to the incident light incident on the display device 51 from the outside is suppressed even if the definition is improved by the following action.
Since the incident light incident on the display device 51 from the outside first passes through the transmittance adjusting layer 5, it is attenuated according to the transmittance of the transmittance adjusting layer 5. When the attenuated light is reflected inside the display device 51 and goes out of the display device, it is attenuated again through the transmittance adjusting layer 5. That is, the incident light incident on the display device 51 from the outside is attenuated to the ratio of the squared value of the transmittance of the transmittance adjusting layer 5 by the time it goes out of the display device again and is visually recognized by the user. For example, when the transmittance of the transmittance adjusting layer 5 in the visible light region is 75%, the incident light incident on the display device from the outside is attenuated to at least 56.25% at the time of incident and emitted to the outside of the display device. do.
As a result, the display device 51 of the present embodiment does not require a circularly polarizing plate because the contrast decrease due to the incident light incident on the display device from the outside is suitably suppressed.

Generally, the reflectance of light at the interface between a transparent substrate such as glass and a black matrix is about 3%, which reduces visibility. In the display device 51 of the present embodiment, the transmittance is reduced from 0.3% to about 1% by the transmittance adjusting layer 5, so that the display quality is improved.
When the amount of carbon added to the transmittance adjusting layer 5 is increased to increase the carbon concentration, the refractive index of the transmittance adjusting layer 5 is increased and the reflectance is increased.

Further, in the display device 51 of the present embodiment, the upper electrode 16 of the LED 3 is connected to the power source via the metal thin film 1b and the transparent conductive film 29. Therefore, the durability of the wiring network is higher than that of the configuration in which power is supplied only by the rigid transparent conductive film.

In the present embodiment, the transparent conductive film 29 and the power supply of the LED 3 may be connected. In this case, power consumption can be suppressed by using parallel wiring. Redundancy is improved, and the reliability of power supply to the LED 3 can be improved.

A second embodiment of the present invention will be described with reference to FIGS. 4 and 5. In the following description, the same reference numerals will be given to the configurations common to those already described, and duplicate description will be omitted.

FIG. 4 is a partial cross-sectional view of the display device 101 according to the present embodiment. The BM substrate 10A has a color filter unit 102 between the black matrix 6 and the light absorbing partition wall 2. As a result, the display device 101 is configured to be capable of color display.
The color filter unit 102 is typically composed of three color filters, a red filter R, a green filter G, and a blue filter B, but the number of colors and the combination of colors of the color filter are appropriately determined according to the intended use. I can decide.

As a red organic pigment applicable to the red filter R, C.I. I. Pigment Red 7, 14, 41, 48: 2, 48: 3, 48: 4, 81: 1, 81: 2, 81: 3, 81: 4, 146, 168, 177, 178, 179, 184, 185, Examples thereof include 187, 200, 202, 208, 210, 246, 254, 255, 264, 270, 272, 279 and the like.
A yellow pigment or an orange pigment may be mixed with these red pigments. As applicable yellow organic pigments, C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37, 37: 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 147, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171 213, 214 and the like can be exemplified.

As a green pigment applicable to the green filter G, C.I. I. Pigment Green 7, 10, 36, 37 and the like can be exemplified. The above-mentioned yellow pigment may be mixed with these green pigments. In addition, a halogenated zinc phthalocyanine green pigment and a halogenated aluminum phthalocyanine green pigment can also be preferably used.

As a blue pigment applicable to the blue filter B, C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64 and the like can be exemplified.
A purple pigment may be mixed with these blue pigments. As a purple pigment, C.I. I. Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50 and the like can be exemplified.

Each of the above-mentioned pigments is used by being dispersed in a transparent resin together with an organic solvent and a dispersant. The transparent resin is preferably a transparent resin having a visible transmittance of 90% or more, and is preferably an alkali-soluble photosensitive resin containing a precursor of the resin. The pigment can be contained in the range of 15% by mass to 65% by mass with respect to the resin.
As a photosensitive resin, a (meth) acrylic compound having a reactive substituent such as an isocyanate group, an aldehyde group, an epoxy group or a silanol group on a linear polymer having a reactive substituent such as a hydroxyl group, a carboxy group or an amino group. A polyimide resin, an epoxy resin, an acrylic resin, a melamine resin, a phenol resin, an oxetane resin, or a siloxane resin in which a photocrossblinking group such as a (meth) acryloyl group or a styryl group is introduced into a linear polymer by reacting with or silicic acid. , Benzoxazine resin and the like can be exemplified. When the photosensitive resin is cured by irradiation with ultraviolet rays having a wavelength of 365 nm or the like, a photopolymerization initiator or the like may be added to the photosensitive resin.

The LED 3 is arranged in the opening of the light-reflecting partition wall 1 as in the first embodiment.
A light scattering layer 28 is arranged in the opening of the light absorbing partition wall 2. The light scattering layer 28 has a structure in which the light scattering particles 28a are dispersed and arranged on a transparent base resin.
As the light scattering particles 28a, optically isotropic transparent fine particles and metal oxide particles can be used. The average particle size of the light scattering particles 28a can be 0.03 μm or more and 5.0 μm or less. "Optically isotropic" means that the transparent fine particles have a crystal structure in which the a-axis, b-axis, and c-axis are equal to each other, or have an amorphous structure (amorphous), and the propagation of light is the crystal axis. Alternatively, it means that it is isotropic without being affected by the crystal structure. The silica fine particles have an amorphous property. As fine particles of resin such as resin beads, fine particles having various properties including a refractive index are known, and these fine particles can be appropriately combined and used in the light scattering layer 28.

Metal oxides include Li, Be, B, Na, Mg, Al, Si, K, Ca, Sc, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, Rb, Sr, Y, Mo. , Cs, Ba, La, Hf, W, Tl, Pb, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Ti, Sb, Sn, Zr, Nb , Ce, Ta, In, can be an oxide containing one or more metals selected from the group. Specifically, Al ₂ O ₃ , SiO ₂ , ZnO, ZrO ₂ , Bathio ₃ , TIO ₂ , Ta ₂ O ₅ , Ti ₃ O ₅ , ITO, IZO, ATO, ZnO-Al, Nb ₂ O ₃ , SnO. , MgO and the like can be exemplified. If necessary, the surface of the metal oxide particles may be surface-treated with a compound having an unsaturated bond such as acrylate.
In the light scattering layer 28, fine particles of resin such as acrylic, styrene, urethane, nylon, melamine, and benzoguanamine can also be used as the light scattering particles 28a. These fine particles may be mixed with the above-mentioned fine particles of the metal oxide.

The light scattering layer 28 can be formed by applying and curing a coating liquid in which light scattering particles 28a are dispersed in a transparent resin together with an organic solvent and a dispersant.
The transmittance of visible light of the transparent resin is preferably 90% or more. As such a resin, an alkali-soluble photosensitive resin containing a resin precursor can be exemplified, and can be the same as the photosensitive resin of the color filter unit 102 described above.

The particle size of the light scattering particles 28a can be appropriately set, but it is preferably larger than the wavelength of visible light from the viewpoint of conversion efficiency or light scattering effect, and can be, for example, about 0.8 μm to 2 μm.
It is preferable that two to five light scattering particles 28a are arranged side by side in the film thickness direction of the light scattering layer 28. For example, when the grain shape of the light scattering particles 28a is 1 μm to 5 μm, the height of the light absorbing partition wall 2 in the film thickness direction is set within the range of 5 μm or more and 25 μm or less, thereby satisfying the above. Can be placed.

In the display device 101 of the present embodiment, a set of an opening in which the red filter R is arranged, an opening in which the green filter G is arranged, and an opening in which the blue filter B is arranged functions as one pixel to display colors. Functions as a possible display device.
The actions and effects of the light-reflecting partition wall 1, the light-absorbing partition wall 2, the transmittance adjusting layer 5, the black matrix 6, and the like in the display device 101 are the same as those in the first embodiment.

In the display device 151 of the modified example shown in FIG. 5, instead of the light scattering layer 28, one of the three wavelength conversion layers of the red conversion layer 25, the green conversion layer 26, and the blue conversion layer 27 is a light absorbing partition wall. It is arranged in the opening of 2.
The red conversion layer 25, the green conversion layer 26, and the blue conversion layer 27 are arranged so as to correspond to the red filter R, the green filter G, and the blue filter B, respectively.

The red conversion layer 25 contains particles of the red phosphor 25a. As the red phosphor 25a, Y ₂ O ₂ S: Eu ³⁺ , YAlO ₃ : Eu ³⁺ , Ca ₂ Y ₂ (SiO ₄ ) ₆ : Eu ³⁺ , LiY ₉ (SiO ₄ ) ₆ O ₂ : Eu ³⁺ , YVO ₄ : Eu ³⁺ , CaS: Eu ³⁺ , Gd ₂ O ₃ : Eu ³⁺ , Gd ₂ O ₂ S: Eu ³⁺ , Y (P, V) O ₄ : Eu ³⁺ , Mg ₄ GeO _5.5 F: Mn ⁴⁺ , Mg ₄ GeO ₆ : Mn ⁴⁺ , K ₅ Eu _2.5 (WO ₄ ) _6.25 , Na ₅ Eu _2.5 (WO ₄ ) _6.25 , K ₅ Eu _2.5 (MoO ₄ ) _6.25 , Na ₅ Eu _2.5 (MoO4) _{6.25 and the} like can be exemplified.
The green conversion layer 26 contains particles of the green phosphor 26a. As the green phosphor 26a, (BaMg) Al ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ , Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ , (SrBa) Al ₁₂ Si ₂ O ₈ : Eu ²⁺ , (BaMg) ₂ SiO ₄ : ^{_{Eu 2+, Y 2 SiO 5:}} Ce 3+, Sr 2 P 2 O 7 -Sr 2 B 2 O 5: Eu 3+, (BaCaMg) 5 (PO 4) 3 Cl: Eu 2+, Sr 2 Si 3 O 8 -2SrCl ₂ : Eu ²⁺ , Zr ₂ SiO ₄ , MgAl ₁₁ O ₁₉ : Ce ³⁺ , Tb ³⁺ , Ba ₂ SiO ₄ : Eu ²⁺ , Sr ₂ SiO ₄ : Eu ²⁺ , (BaSr) SiO ₄ : Eu ^{2+ and the} like can be exemplified.
The blue conversion layer 27 contains particles of the blue phosphor 27a. As the blue phosphor 27a, Sr ₂ P ₂ O ₇ : Sn ⁴⁺ , Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , SrGa ₂ S ₄ : Ce ³⁺ , CaGa ₂ S ₄ : Ce ³⁺ (Ba, Sr) (Mg, Mn) Al ₁₀ O ₁₇ : Eu ²⁺ , (Sr, Ca, Ba ₂ , Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , BaAl ₂ SiO ₈ : Eu ²⁺ , Sr ₂ P ₂ O ₇ : Eu ²⁺ , Sr ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , (Sr, Ca, Ba) ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , BaMg ₂ Al ₁₆ O ₂₇ : Eu ²⁺ , (Ba) , Ca) ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , Ba ₃ MgSi ₂ O ₈ : Eu ²⁺ , Sr ₃ MgSi ₂ O ₈ : Eu ^{2+ and the} like can be exemplified.

A liquid crystal substrate 300 is arranged between the light-absorbing partition wall 2 and the light-reflecting partition wall 1. The liquid crystal substrate 300 has a known configuration including a liquid crystal layer 301 and an array substrate 302 including a transistor for driving the liquid crystal layer, and functions as a display function layer. In the liquid crystal substrate 300, the horizontally oriented liquid crystal may be driven by the method of FFS (fringe field switching).

The grid pattern of the light-reflecting partition wall 1 according to the display device 151 is one for each pixel consisting of an opening in which the red filter R is arranged, an opening in which the green filter G is arranged, and an opening in which the blue filter B is arranged. It forms an opening. That is, three LEDs 3 are arranged in one opening. In FIG. 5, the transparent conductive film 29 is omitted, but in the cross section from the direction (left or right of the paper surface) in which FIG. 5 is horizontally rotated by 90 degrees, the transparent conductive film has the same embodiment as that of FIG. 29 and the LED are connected.

In the display device 151 having the above configuration, the displayed shape, pattern, and the like are exclusively controlled by the liquid crystal substrate 300, and the LED 3 basically functions as a direct type backlight. In this case, each LED 3 does not have to be individually turned on and off.
The light emitted from each LED 3 passes through the liquid crystal layer 301 and then passes through the corresponding wavelength conversion layers 25, 26, and 27 to convert the wavelength and becomes the color light of the corresponding color filter. As a result, it is possible to display with high color purity.
The actions and effects of the light-reflecting partition wall 1, the light-absorbing partition wall 2, the transmittance adjusting layer 5, the black matrix 6, and the like in the display device 151 are the same as those in the first embodiment.
Since the display device 151 has a wavelength conversion layer, in addition to the white LED, an LED having a wavelength of emitted light in the near-ultraviolet region such as 365 nm, 385 nm, and 395 nm can be used as the LED 3.

Various changes can be made in the display devices 101 and 151. Some of them are shown below, but not all of them, and other changes are possible. Further, a plurality of these changes may be combined as appropriate.

In the display device 101, the red conversion layer 25, the green conversion layer 26, and the blue conversion layer 27 may be provided instead of the light scattering layer 28.
In the display device 151, the color filter unit 102 may be omitted.
In the display devices 101 and 151, the LED corresponding to the blue filter B may be a blue LED, and the blue conversion layer 27 may be a light scattering layer 28.

-In the wavelength conversion layer, quantum dots may be used instead of the phosphor.
-Light scattering particles may be added to the wavelength conversion layer to impart light scattering properties.

The display device according to this embodiment can be applied in various ways. Specifically, mobile phones, portable game devices, mobile information terminals, personal computers, electronic books, video cameras, digital still cameras, head mount displays, navigation systems, sound reproduction devices (car audio, digital audio players, etc.), It can be applied to electronic devices such as copiers, facsimiles, printers, multifunction printers, vending machines, automatic cash deposit / payment machines (ATMs), personal authentication devices, optical communication devices, and IC cards. An antenna may be further mounted on the electronic device on which the display device according to the present invention is mounted, so that communication and non-contact power supply / reception may be possible.

Although each embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and changes and combinations of configurations within a range that does not deviate from the gist of the present invention are also possible. included.

For example, the light emitting element of the light emitting unit is not limited to the LED, and an organic EL (organic electroluminescence) also called an OLED (Organic Light Emitting Diode) can be used.

Further, the light absorbing partition wall may be formed on the optical module substrate side.
Further, when silver is used for the metal thin film of the light-reflecting partition wall, since the adhesion between silver and the resin is low, a transparent conductive film may be provided between the core and the metal thin film to improve the adhesion between the two. By doing so, the structure of the contact portion between the metal thin film and the transparent conductive film becomes substantially the same as that of the reflective electrode.

1 Light-reflecting partition 2 Light-absorbing partition 3 LED light-emitting element 4 Light-emitting unit 5 Transmittance adjustment layer 6 Black matrix 25 Red conversion layer (wavelength conversion layer)
26 Green conversion layer (wavelength conversion layer)
27 Blue conversion layer (wavelength conversion layer)
28 Light scattering layer 31 Reflective electrode 40 Channel layer 45 Metal layer 46 Conductive oxide layers 51, 101, 151 Display device 100 First substrate 100a First surface 102 Color filter unit 200 Second substrate

Claims (13)

The first substrate with the first surface and
A second substrate having a second surface and arranged with the second surface facing the first surface,
A black matrix provided in a matrix on the first surface and having a plurality of openings,
A transmittance adjusting layer provided between the first surface and the black matrix and containing carbon,
A plurality of light emitting units including a light emitting element arranged in a matrix on the second surface, and
A light-reflecting partition wall provided in a matrix on the second surface and surrounding the plurality of light emitting units in a plan view,
A light-absorbing partition wall containing carbon and provided in a matrix and arranged between the first surface and the light-reflecting partition wall,
To prepare
Display device. The light-reflecting partition wall has a metal thin film and has a metal thin film.
The metal thin film constitutes a part of the power feeding wiring of the light emitting element.
The display device according to claim 1. Further provided with a transparent conductive film electrically connected to the metal thin film,
The metal thin film and the transparent conductive film are each connected to a power source of the light emitting element.
The display device according to claim 2. The light emitting unit has a thin film transistor that drives the light emitting element.
At least a part of the wiring of the thin film transistor has a structure in which a metal layer is sandwiched between conductive oxide layers.
The display device according to claim 1. The light emitting unit has a reflective electrode and has a reflecting electrode.
At least a part of the reflective electrode has a structure in which a metal layer is sandwiched between conductive oxide layers.
The display device according to claim 1. The display device according to claim 4, wherein the channel layer of the thin film transistor is made of an oxide semiconductor. The light-reflecting partition wall has a matrix shape, and is located within a range provided with the black matrix and the light-absorbing partition wall in a plan view of the display device.
The display device according to claim 1. The visible light transmittance of the transmittance adjusting layer is 70% or more and 99.5% or less.
The display device according to claim 1. The display device according to claim 1, wherein the light-reflecting partition wall is thicker than the black matrix. The transmittance of light having a wavelength of 365 nm in the thickness direction of the light-absorbing partition wall is 0.1% or more and 10% or less.
The display device according to claim 1. Further comprising a wavelength conversion layer disposed at the opening of the matrix of the light absorbing partition.
The display device according to claim 1. Further comprising a light scattering layer disposed at the opening of the matrix of the light absorbing partition.
The display device according to claim 1. A color filter unit arranged in the opening of the black matrix is further provided.
The display device according to claim 1.

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